Institute of Ecology, Diversity and Evolution, Goethe University Frankfurt, Frankfurt am Main, Germany.
Department of Geodynamics, Stratigraphy and Paleontology, Complutense University of Madrid, Madrid, Spain.
Sci Rep. 2023 Jun 26;13(1):10323. doi: 10.1038/s41598-023-37135-8.
Understanding the changing plant ecosystems that existed in East Africa over the past millennia is crucial for identifying links between habitats and past human adaptation and dispersal across the region. In the Horn of Africa, this task is hampered by the scarcity of fossil botanical data. Here we present modelled past vegetation distributions in Ethiopia from the Last Glacial Maximum (LGM) to present at high spatial and temporal resolution. The simulations show that, contrary to long-standing hypotheses, the area covered by Afromontane forests during the Late Glacial was significantly larger than at present. The combined effect of low temperatures and the relative rainfall contribution sourced from the Congo Basin and Indian Ocean, emerges as the mechanism that controlled the migration of Afromontane forests to lower elevations. This process may have enabled the development of continuous forest corridors connecting populations that are currently isolated in mountainous areas over the African continent. Starting with the Holocene, the expansion of forests began to reverse. This decline intensified over the second half of the Holocene leading to a retreat of the forests to higher elevations where they are restricted today. The simulations are consistent with proxy data derived from regional pollen records and provide a key environmental and conceptual framework for human environmental adaptation research.
了解过去几千年来东非不断变化的植物生态系统对于确定栖息地与该地区过去人类适应和扩散之间的联系至关重要。在非洲之角，由于化石植物数据的稀缺，这项任务受到了阻碍。在这里，我们提出了过去在埃塞俄比亚的植被分布的模拟结果，时间范围从末次冰盛期（LGM）到现在，具有较高的时空分辨率。模拟结果表明，与长期以来的假设相反，在晚冰期，Afromontane 森林所覆盖的面积明显大于现在。低温和源自刚果盆地和印度洋的相对降雨量的综合作用，是控制 Afromontane 森林向低海拔地区迁移的机制。这一过程可能使连接目前在非洲大陆山区隔离的人群的连续森林走廊得以发展。从全新世开始，森林的扩张开始逆转。在全新世的后半段，这种下降趋势加剧，导致森林退回到今天仍然局限于高海拔地区。这些模拟结果与区域花粉记录得出的代理数据一致，并为人类环境适应研究提供了关键的环境和概念框架。
